Cassius Dio. Roman History LXII 3: "Nero admired him for this action and entertained him in many ways, especially by giving a gladiatorial exhibition at Puteoli. It was under the direction of Patrobius, one of his freedmen, who managed to make it a most brilliant and costly affair, as may be seen from the fact that on one of the days not a person but Ethiopians — men, women, and children — appeared in the theatre." https://penelope.uchicago.edu/Thayer/E/Roman/Texts/Cassius_Dio/62*.html#29